Sorry for confusion.
I am not trying to add new button but want to change alignment of SharePoint “Save and Cancel” from right aligned to left aligned.
Why it is required?
As I am using side by side settings, Save and Cancel buttons are out of screen and we need to scroll to right to find them.
However, what I need is I have 4 rows in form where I am capturing details. For each detail, I need to keep attachment field so that users can attach row related attachment.